M10 hard washer

There are certain fasteners on a car which require use of a high quality hardened washer, and a regular washer simply is not good enough for the job.  These are often torque critical items such as main bearing caps, underneath cylinder head bolts or nuts.   

This washer is for an M10 fixing, so has an ID of just over 10mm, an OD of 19mm (3/4") and measures 3mm thick.